Gun type oil burner



11 1950 R. E. NEST 2,502,664

GUN TYPE OIL BURNER Filed Oct. 6, 1947 s Sheets-Sheet 1 INVENTQR.RICHARD E. NEST ATTORNEY Aprifl 4, 1950 R. E. NEST 2,502,664

GUN TYPE OIL BURNER I s Sheetsl-Sheet 2 Filed Oct. 6, 1947 v vq M I Wa!" 15 I w W 3 L w m D O i a s N a INVENTOR.

RICHARD "1 NEST BYM W ATTORNEY April 4, 11950 I NEST 2,502,664

GUN TYPE OIL BURNER Filed 001). 6, 1947 3 Sheets-Sheet 3 INVENTOR.RICHARD 5. N53? Patented Apr. 4, 1950 UNITED STATES ATENT OFFECE GUNTYPE OIL BURNER,

Richard E. Nest, Baltimore, Md., assignor to The General Oil BurnerCorporation, a corporation of Maryland 6 Claims.

This invention relates to combustion burners adapted to burn fluidfuels, and more particularly to pressure atomization for use with liquidhydrocarbon fuels.

In the early development of oil burners little thought was given to theproper mixing of the air and oil spray for combustion purposes. Thefires did not burn clean even when excessive amounts of air were usedwhich reduced the carbon-dioxide concentration of the waste gases to 6or 7% by volume. This method wasted con siderable fuel.

Further improvement of the pressure atomizing burner with respect to thecombustion results revolved around the fact that by imparting aspiralling or rotating motion to the air within the blast tube of theburner the resulting combustion reaction could be noticeably improved.Numerous and ingenious devices consisting essentially of directing vaneswere developed with generally improved results. There followed a periodwherein a carbon-dioxide concentration of 10% without objectionablesmoke was adopted as a laboratory test standard and seemed to be thelimit. With the present dependence upon petroleum products and itsproblem of supply new and more economical refining methods are requiredto supply the demand. The process of catalytic cracking came to thefront and with it a change in the chemical structure of the fuel oilmolecule. This change of structure set up a new set of conditions forthe oil burner and while the carbon to hydrogen ratio changed in such away as to require slightly more air per gallon of fuel burned theincrease was not suilicient to provide the velocity required nor was theproblem one of the plain forward velocity. In general when air is causedto rotate or spiral through the blast tube of an oil burner themolecules that make up the air stream have imparted to them at least twodirectional forces. One of these forces may be considered as a forwardcomponent While the other tends to deflectsidewise by reason of whateverobstruction or deflecting means started the motion. So long as such anair stream is confined within a tube said stream Will revolve withinthose confines. To some degree an inwardly converging restriction in thedischarge end of the blast tube will increase the rotational speed atthe point of discharge. principle is the basis for the design of thenozzle used to spray the fuel oil. However, upon leaving the confines ofthe tube the air particles still endowed with propelling energy will notcontinue along any similar path as was followed within the This 2 tube.They assume a new path or trajectory and due to the effect of the abovementioned dual directional forces assume a relatively straight lineflight, the path of which is a resultant lying somewhere between theforward direction and the side one.

The resulting pattern if reproduced photographically would appear in theshape of a hollow cone diverging from the source. counteracting forceswill enter into the movement of the air particles and the finalconditions within a flame so supplied with air will be indeterminate.Such conditions as above described, will also set up at least one resultthat is less favorable to the successful operation of the burner. Byexploring the opening at the discharge end of a blast tube by means ofan impact tube and manometer there will be found to exist an areacentrall located and concentric with the opening that shows negativegauge pressures while adjacent to the walls or orifice the pressure willbe positive. This condition will in operation cause unburned sootydeposits to form on the fuel nozzle and the electrodes. Therecirculating hot gases and burning products often cause excessivecarbonization of these parts. Various means have been applied toovercome these objectionable features with more or less success. Whenattempting to burn very small quantities of oil, about one gallon perhour or less, the amount of air becomes proportionately less, strivingfor higher efficiencies reduces the air volume still further. The fuelnozzle and the ignition electrodes are positioned in spaced relation toeach other and of necessity, require certain clearances with respect tothe orifice or opening at the end of the blast tube. Thus a minimumopening size is established without any consideration being given to theair flow. If the air velocity is reduced to satisfy the metering effectof the orifice said velocity will be insufficient to effectively mix thefuel spray and air with the result that the fire will be extremely dirtyand may even smother for want of oxygen at the proper location. Theanswer will be found in the two directional force theory to be describedin this application. By separating the main air stream into amultiplicity of overlapping streams of air issuing into a form thatresembles ribbons, as with the air register under discussion. it hasbeen found that within limits the air can be given an initial directingforce similar to the result obtained when using a conventional form ofair deflector. By arranging the louvre shaped openings on a conicallyshaped surface the gross area may be increased while maintaining theminimum of slot width. Such a relationship results in a better jetaction and maximum deflection of the air streams. The concave side ofthe air register when on the fire side further provides a most effectivechamber for the mixing or blending of the multiple issuing jets of air.By partially restricting or deflecting these multiple air jets by meansof proportioned orifices located concentrically with the air registerand at a point of greatest diameter the control of the final delivery isaccomplished. A minimum sized orifice delivers a minimum amount of airwhile all the air is deflected at least twice prior to final discharge.With an increase of orifice size the second deflecting action isproportionally decreased while the air deflected only once is dischargedin essentially the desired direction.

The main air stream controls the shape and quality of the resultingcombustion and by the introduction of a stabilizing air stream into thevortex of the said resulting action controls the point of flame front orflame propagation.

The result of these forces is manifest in a fire at all rates that isactive due to relatively high air velocities. Said fires are eificientdue to this velocity discharge with proportioned air volumes. Also ofimportance the fire is highly stable due to the resulting stable vortexat the point of flame propagation.

It is an object of the present invention to deliver fuel and air in suchproportions that combustion may be readily established through ignitionmeans and continue thereafter under equilibrium conditions of exothermalreaction while maintaining maximum efiiciencies.

It is an additional object of the present invention to provide a guntype burner having improved means fo supplying main and stabilizing airstreams and directing them in controlled relationship to each other andto the oil spray, characterized by the production of a steady, stableand quiet flame of high temperature and by improved efficiency ofcombustion.

It is an additional object of the present invention to provide a guntype burner having an improved method of introducing air for the purposeof combustion with respect to the oil spray and comprises in changingthe size of the orifice in the nose piece to suit the size of the firerequired, it being noted that as the orifice opening is increased moreair goes off tangentially causing a reduction in the whirling action.

It is an additional object of the present invention to provide an outertube and a dividing tube to guide the main air stream to the nose pieceorifice and having means for supplying a controllable stabilizing airsupply to control the point of flame propagation so it will occur at apoint outside of the nose ring and prevent the creation of a vacuumwhich would cause the combustion to take place in back of the nose ring.

It is an additional object of the present invention to provide an oilburning means in which increasing the orifice opening will cause moreair to leave the burner tangentially, with the resulting reduction ofthe whirling action of the air to produce better combustion with lessheat losses.

It is an additional object of the present invention to provide an oilburner with air controlling means to more effectively burn the aromaticfuels produced through catalytic cracking.

It is an additional object of this invention to provide an oil burnerhaving nose pieces provided with orifice opening proportioned to suitthe size of oil nozzle used and providing a stabilizing air supplypreferably adjustable from the outside of the burner to enable the oilburner to burn cleanly and be free from objectional combustion rumblingand pulsations while maintaining combustion efilciency.

t is an additional object of this invention to provide air control meanswhich can be adapted to existing fuel oil burners to enable them to beoperated by catalytically cracked oils efficiently.

Other objects will become apparent as the invention is more fully setforth.

For a better understanding of the invention, its objects and theprinciples thereof, reference is made to the appended drawings and thefollowing description, wherein together, is outlined and illustrated aparticular form of the invention by wa of example, while the scope ofthe invention is indicated in the claims.

In the drawings:

Figure 1 is a side elevation of the oil burner embodying this inventionwith parts broken away to show its inner construction;

Figure 2 is an enlarged sectional view taken along lines 2-2 of Figure1;

Figure 3 is a sectional view taken along line 33 of Figure 1;

Figure 4 is an end view, partly in section, of the burner looking in thedirection of lines 4-4 of Figure 2;

Figure 5 is a sectional view taken along lines 55 of Figure 1;

Figure 6 is a sectional view taken along lines G-6 of Figure 1;

Figure '7 is a sectional view taken along lines 7-! of Figure 1;

Figure 8 is a sectional view taken along lines 88 of Figure 4.

Similar reference characters refer to similar parts throughout thedrawings.

In the particular construction shown in the drawings, the fan housing isprovided at its discharge opening with a blast tube 2 suitably attachedto the fan housing I and in locking attachment to the discharge end ofthis tube is the burner nose piece 3, which is preferably in the form ofa cup shaped stamping of heat resisting material. The bottom or fire endof said nose piece has an opening or orifice 4 therein preferably roundand concentric with the main body thereof, the size of which dependsupon the firing rate. This nose piece acts as a restricting member forthe control of the air volume. At the lowest point of said nose piece 3and on the same plane as the orifice 4, is a small opening 5 to preventthe accidental accumulation of oil in the blast tube 2. Inside the blasttube 2, and in removable attachment thereto is preferably positioned asupporting bracket 6, the fire end of which is suitably formed to bothlocate and support an inner dividing tube 1. The dividing tube 1, ispreferably of tubular section having a conical restriction or transition8, at its discharge end, said small end being provided with a groove 20to receive and be mechanically affixed to the air register 9. The airregister 9, is preferably a cup shaped section consisting of a verticalsection essentially round in form and having a hole 2| therein ofsuitable size to conform and be fitted with the groove 20 of therestriction 8 of the dividing tube 1. From the outer periphery of saidvertical surface the air register 9 continues in the form of a truncatedcone, the sides of which diverge from the aforementioned verticalsurface toward the firing end of the burner preferably as shown inF-igures '1 and 2. At the extreme diameter of said conicalsection theair register is terminated in a short section of parallel wall forming acylindrical stiffening ring ill, said ring being of suitable dimensionto slipinto positioning support of the nose piece 3. Figures 4 and 8show an end view and section of the air register 9-. Located on theconical surfaces of said air register and in radially-spacedrelationshipthereon are embossed a multiplicity of slit openings l I. Said openingsbeing preferably in the form of louvres- H.

An oil line l3 passes through the fan housing 1 and extends along thelongitudinal axis of the blast tube 2 and dividing tube 1, and issuitably connected to a fuel delivery assembly M. The assembly l4consists of conventional incidental parts comprising a nozzle, strainer,and nozzle body or adapter, and will not be described herein. Itthree-point supporting spider l5 adjustably affixed to the oil line [3bymeans of a set screw 22 is positioned Within the dividing tube l tomaintain axial alignment of the fuel delivery assembly M with respect tothe nose piece 3. A further purpose of said spider is to provide asuitable supporting means for the attachment and. relational spacing ofthe ignition electrodes 1 6 which are held thereto by clamps 42. Inslidable bearing on the oil line l3 and positioned towards the fan sideof the dividing tube 1 is a disc I! which is mounted on a sleeve I8which has its end flared outwardly to contact and control the movementof the disc H. The disc [1 is provided with holes. for the clearance oftheprojecting electrodes l6 which act to prevent the rota! tion of saiddisc ll. The sleeve I 8 may be controlled in its movements by variousmechanisms but inthe drawings is provided with a split clamp 23 havingon the underside a suitable projection 24 to receive in pivotableconnection thereto a motion transmitting link 25. Suitably spaced andclamped to the oil line l3 and in the direction approaching the fan is asupporting member 26 extending horizontally and perpendicular to theaxis of said oil line. Attached to the outer end of said supportingmember and extending downwardly is a projection 21 to receive and retainin pivotal attachment a bell lever 23. Said bell lever has one arm 29extending preferably parallel to the oil line l3. The arm 29 is soshaped and proportioned with a shoulder 32 as to be manually actuatedthrough a pressure contact of an adjusting screw 30 located through thefan housing I. The bell lever 28 is preferably tensioned by a spring 3|attached to the supporting member 26. The link 25 transfers longitudinalmotion from the bell lever 28 to the sleeve l8 and disc IT. The blasttube 2 is preferably attached to the fan housing I by means of screws33. The oil line [3 is provided with the conventional fittings 34 forconnecting it to the conventional fuel oil source.

The dividing tube 1, is preferably provided with a fitting 35 having adove tailed slot 36' for slidably positioning on the supporting bracket6 which is formed to suit. The fitting 35 not only supports the dividingtube 1 but also allows it to be adjusted backwardly and forwardly inrelation to the assembly 14 to suit the firing conditions required.

The motor, oil filters, transformers, pumps and other equipment notspecifically mentioned are of the conventional types and do not form apart of this invention.

In operation, an oil burner of the type described would be provided witha fuel delivery assembly Id of predetermined capacity, the fuel theretobeing supplied at constant. pressure. A nose piece 3, having an orifice4 of suitable size to suit said oil nozzle would be attached to theblast tube 2. The air from the burner fan withoutrecourse to any otheradjustment will be delivered through the orifice 4 in essentially theright amount for the particular firing rate. The relationship of the airregister 9 and the orifice 4 provide the pattern of the issuing airstream which in turn controls to a large degree the resulting flameshape. Movement of the disc I! to or from the inner end 36 of thedividing tube 1 by means of suitable controlling means preferably suchas has been described, acts as a valve. Said valve action controlling asmall portion of the air and admitting same as a jet into the vortex ofthe air chamber formed in the space between the air register 9 and nosepiece 3. By proportional relationship of the bell lever arms and lead orpitch of the adjusting screw 30 in contact therewith very close controlof the valve disc I! is obtained even with the burner in operation. Theapproximate opening of this valve disc I l for the various firing ratesmay be predetermined to such a degree that settings may be made byreference to a, printed table and final nice adjustment can then be madethrough the fan air inlet control, using a gas analyser for reference ifdesired. One outstanding result in the use ofthis device has been foundto be that even when the burner has been adjusted by one having littleexperience in the art and without the aid of a gas analyzing apparatusthe results are generally far superior to the best adjustment obtainableon many burners of prior design.

While but one general form of the invention is shown in the drawings anddescribed in the specifications, it is not desired to limit thisapplication for patent to this particular form or in any other wayotherwise than limited by the scope thereof, as it is appreciated thatother forms of construction could be made that would use the sameprinciples and come within the scope of the appended claims.

Having thus described the invention, what is claimed is:

1. In a burner the combination comprising a blast tube, means forsupplying air to said blast tube, a conduit in fiow communication with afuel supply and passing through said blast tube, a fuel nozzlepositioned on the burner end of said conduit, a spider slidablypositioned on said conduit within said blast tube, a supporting bracketattached to the internal portion of said blast tube, a dividing tubeslidably positioned on said supporting bracket and spider, an airregister positioned on the firing end of said dividing tube andshiftable for adjustment relative to said blast tube, a sleeve membermounted on said conduit, a disc mounted on said sleeve, and meansadjustably positioning said disc in relation to the end of the dividingtube towards the fan housing for separating a portion of the air supplyfrom the blast tube to create a stabilizing air current through saiddividing tube.

2. In a burner the combination comprising a blast tube, means forsupplying air to said blast tube, a conduit in flow communication with afuel supply means and passing through said blast tube, a fuel nozzleattached to the burner end of said conduit, a spider positioned on saidconduit, a supporting bracket attached to the internal portion of saidblast tube, a dividing tube positioned on said supporting bracket andspider within said blast tube, means attached to the firing end of saiddividing tube for dispersing the air from the blast tube, and shiftablefor adjustment relative to said blast tube and an adjustable means forcontrolling the admission of a stabilizing air stream through saiddividing tube.

3. In a burner the combination comprising a blast tube, means forsupplying air to said blast tube, a conduit in flow communication with afuel supply means and passing through said blast tube, a fuel nozzleattached to the burner end of said conduit, a spider positioned on saidconduit, a supporting bracket attached to the internal portion of saidblast tube, a dividing tube positioned on said supporting bracket andspider within said blast tube, means attached to the firing end of saiddividing tube for dispersing the air from the blast tube, and shiftablefor adjustment relative to said blast tube and adjustable means forcontrolling the admission of a stabilizing air stream through saiddividing tube, a nose piece for attachment to the fire end of said blasttube.

4. In a burner the combination comprising a blast tube, means forsupplying air to said blast tube, a conduit in flow communication with afuel supply means and passing through said blast tube, a fuel nozzleattached to the burner end of said conduit, a spider positioned on saidconduit, a supporting bracket attached to the internal portion of saidblast tube, a dividing tube positioned on said supporting bracket andspider within said blast tube, means attached to the firing end of saiddividing tube, for dispersing the air from the blast tube and shiftablefor adjustment relative to said blast tube, an adjustable means forcontrolling the admission of a stabilizing air stream through saiddividing tube, a nose piece for attachment to the fire end of said blasttube, said nose piece having an orifice in its end portion.

5. In a burner the combination comprising a blast tube, means forsupplying air to said blast tube, a conduit in flow communication with afuel supply means and passing through said blast tube, a fuel nozzleattached to the burner end of said conduit, a spider positioned on saidconduit, a supporting bracket attached to the internal portion of saidblast tube, a dividing tube positioned on said supporting bracket andspider Within said blast tube, means attached to the firing end of saiddividing tube for dispersing the air from the blast tube, and shiftablefor adjustment relative to said blast tube, an adjustable means forcontrolling the admission of a stabilizing air stream through saiddividing tube, a nose piece for attachment to the fire end of said blasttube, said nose piece having an orifice in its end proportioned to suitthe size of the fuel nozzle used.

6. In a fluid fuel burner, the combination with a fuel nozzle adapted todeliver a spray of fuel, a dividing tube positioned over the fuel nozzlebut spaced therefrom, a blast tube positioned in spaced relationshipover said dividing tube to create an air passage therebetween, saiddividing tube being slidably mounted along said blast tube, airdeflecting means attached to said dividing tube and slidably positionedin said blast tube for directing an air stream through the burner end ofsaid blast tube, and means for providing a stabilizing air stream thatwill pass through said dividing tube and over the said fuel nozzle toposition the point of flame propagation in said burner.

. RICHARD E. NEST.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,640,729 Scott Aug. 30, 19271,706,316 Norton et al Mar. 19, 1929 1,719,090 Stillman July 2, 19291,777,141 Howden Sept. 30, 1930 2,120,387 Bargeboer June 14, 19382,163,915 Reif et al. June 27, 1939 2,221,519 Jones et a1 Nov. 12, 19402,262,525 De Lancey Nov. 11, 1941 2,393,897 Glendenning Jan. 29, 1946

